• Polymer(Korea)
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• v.36 no.6
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• pp.699-704
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• 2012

Double-layered polymeric carrier was designed for release control of hydrophilic drug in oral administration. Biopolymeric chitosan and alginate were examined as polar absorbents, poly(D,L-lactide) as a hydrophobic shell, and theophylline and diclofenac sodium as loading drugs. The fabrication of the carriers was prepared in the form of double-layered microsphere for delayed and successively extended release, which consisted of outer shell of poly(D,L-lactide) and inner core of alginate or chitosan with drugs. Morphologies and drug-release behaviors of the carriers were investigated, which were influenced by a combination of polarity between carrier and drug. It was confirmed that the relative polarities of the carriers, the drugs, and the environmental pH affected significantly the drug-release property.

• Journal of the Korean Society of Radiology
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• v.11 no.5
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• pp.353-359
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• 2017

The sonophoresis, a representative low-intensity ultrasonic therapy, is a technique for delivering the drugs into the epidermis, dermis and skin appendages by using physical vibration and heat effects of the ultrasonic waves. Sonophoresis could increases the delivering and absorption efficiency of the drugs usually consisting of hydrophilic molecules and macromolecules. In addition, it has the advantage of being effective in delivering drugs with relatively large molecular sizes such as insulin or lipid. In this study, we proposed a multi-structure ultrasonic transducer assembly with a large-size single piezoelectric element and a drug delivery function at the treatment site for efficient sonophoresis treatment. Futhermore, a transducer assembly structure capable of raising and maintaining the temperature of the treatment site was proposed and evaluated for effectiveness. The transducer assembly proposed in this study is expected to improve the efficiency of sonophoresis by providing a constant amount of drug, and assisting drug delivery through heating the treatment site.

• Biomolecules & Therapeutics
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• v.7 no.2
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• pp.191-197
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• 1999

The effects of various drugs on the alleviation of the symptoms of chemical bums were evaluated in mice to formulate topical antiblister preparations. After a chemical bum was induced on the mouse dorsal skin with 2-chloroethylethyl sulfide, the drug was applied on the disease site. The effectiveness of the drug was evaluated by determining blister size, necrosis score of skin and appearance of the chemical burns induced. It showed that steroids and aminoglycoside antibiotics had a tendency to protect skin cell, and antihistamines decreased the size of chemical bums. While oleaginous base resulted in deleterious effect, hydrophilic base didn't show a significant difference on the alleviation of the chemical burn symptoms compared to the control.

• Polymer(Korea)
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• v.36 no.4
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• pp.500-506
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• 2012

In this study, we developed and optimized hydrophilic polymer based solid dispersion formulations (SDs) for enhancing the aqueous solubility of eprosartan, one of poorly soluble drugs, that has been broadly used for the treatment of high blood pressure. Poly(ethylene glycol) (PEG) and poly(vinyl pyrrolidone) (PVP) based SDs were prepared by hot melting and solvent evaporation methods and the drug/polymer composition varied in the range of 1:1~1:5 with or without poloxamer 407 (P407) as a polymeric surfactant. The SDs prepared by solvent evaporation showed more reduced crystallinity than ones by hot melting, and PVP based SDs showed more enhanced solubility and lower crystallinity than PEG based SDs. Furthermore, it was observed from DSC and PXRD analysis that the SDs with P407 (drug:polymer: P407 = 1:5:1) demonstrated no crystallinity and the most enhanced solubility (more than 3~4 times).

• Polymer(Korea)
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• v.37 no.4
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• pp.442-448
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• 2013

In this study, we developed and optimized hydrophilic polymer-based solid dispersion formulations (SDs) using a spray drying method for improving the aqueous solubility of eprosartan, one of poorly soluble drugs that has been broadly used for the treatment of high blood pressure. Hydroxylpropylcellulose (HPC) and poly(vinyl pyrrolidone) (PVP) were used as hydrophilic polymer matrices and poloxamer 407 (P407) added as a polymeric surfactant. Various kinds of solid dispersions with different drug/polymer compositions were prepared and their physico-chemical properties were compared. As the polymer content increased, the drug crystallinity in the SDs significantly decreased and the dissolution properties were enhanced. The PVP based SDs were observed to have relatively reduced crystallinity and an enhanced dissolution rate than HPC-based SDs, due to better miscibility between drug and polymer matrix. For PVP based SDs, the drug crystallinity almost disappeared and the dissolution properties significantly increased by more than 3~7 times.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.7
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• pp.2451-2458
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• 2010

We prepared sustained release matrix system which contains carvedilol with Compritol 888 ATO used as lipophilic sustained release excipient and hydroxypropyl methyl cellulose (HPMC) or polyethylene oxide (PEO) used as hydrophilic sustained release polymer. Wet granulation compressed method was used for preparing carvedilol sustained release matrix tablets. When carvedilol sustained release matrix tablets were prepared, we evaluated the drug release kinetics which is affected by Compritol 888 ATO ratio, a kind of hydrophilic polymer (HPMC, PEO) and hot melt coating coagglutination (HMCC) process was done. The drug release kinetics was measured for 24 hours in pH 1.2 simulated gastric fluid and pH 6.8 simulated intestinal fluid, using a dissolution tester at $37.5^{\circ}C$ in 50 rpm. Dissolution rate of controlled release matrix tablets of carvedilol was evaluated by paddle method. We confirmed that HMCC process was very effective to controlled release of drugs. The rate of Compritol 888 ATO, as a lipidic material, can control the drug release pattern about the elution rate of 95% and 24 hours delay than that of the normal tablet.

• Polymer(Korea)
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• v.36 no.4
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• pp.455-460
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• 2012

Poly(N-isopropylacrylamide) (PNIPAM) hydrogel has been studied as an important drug delivery system due to its volume transition or temperature-responsive swelling properties, whose phase separation temperature is similar to the body temperature. However, because of hydrophilic PNIPAM, hydrophobic drugs are difficult to be uniformly loaded in the networks. Antioxidant alpha-lipoic acid (LA) can be prepared as a polymer(polylipoic acid, PLA) by ring opening polymerization, which is hardly developed as a material due to its low molecular weight and easy depolymerization. To overcome this limitation, a hydrophobic active ingredient, LA was reacted with NIPAM into stable hydrogels. Simple thermal radical reaction successfully resulted in a hydrogel (PNIPAM/PLA), which was confirmed by DSC, FTIR, and Raman spectroscopy. The PNIPAM/PLA showed temperature-responsive properties, and their volume swelling decreased with an increase in lipoic acid content. These hydrogels can carry hydrophobic drugs with PNIPAM and the hydrogels could be useful as final drug delivery systems having lipoic acid as an antioxidant.

• Archives of Pharmacal Research
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• v.28 no.7
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• pp.866-874
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• 2005

The objective of this study was to elucidate the feasibility to improve the solubility and bioavailability of poorly water-soluble itraconazole via solid dispersions by using supercritical fluid (SCF). Solid dispersions of itraconazole with hydrophilic polymer, HPMC 2910, were prepared by the aerosol solvent extraction system (ASES) under different process conditions of temperature/pressure. The particle size of solid dispersions ranged from 100 to 500 nm. The equilibrium solubility increased with decrease (15 to 10 MPa) in pressure and increase (40 to $60^{\circ}C$) in temperature. The solid dispersions prepared at $60^{\circ}C$/15 MPa showed a slight increase in equilibrium solubility (approximately 27-fold increase) when compared to pure itraconazole, while those prepared at $60^{\circ}C$/10MPa showed approximately 610-fold increase and no endothermic peaks corresponding to pure itraconazole were observed, indicating that itraconazole might be molecularly dispersed in HPMC 2910 in the amorphous form. The amorphous state of itraconazole was confirmed by DSC/XRD data. The pharmacokinetic parameters of the ASES-processed solid dispersions, such as $T_{max},\;C_{max},\;and\;AUC_{0-24h}$ were almost similar to $Sporanox_{\circledR}$ capsule which shows high bioavailability. Hence, it was concluded that the ASES process could be a promising technique to reduce particle size and/or prepare amorphous solid dispersion of drugs in order to improve the solubility and bioavailability of poorly water-soluble drugs.

• Journal of Pharmaceutical Investigation
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• v.25 no.2
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• pp.153-161
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• 1995

Alginic acid is a hydrophilic , colloidal polysaccharide obtained from cell wall of seaweed or brown algae and has a broad range of applications. Alginlc acid becomes alginate gel bead due to its cation-induced gelation. Dried alginate beads can be reswollen according to environmental pH. The purpose of this paper is to explore the possible applicability of alginate beads as an oral controlled release system of ibuprofen. In this experiment ibuprofen was incorporated in alginate beads and alginate beads were treated with various methods. Ibuprofen release from alginate beads in phosphate buffer (pH 7.4) was laster than in distilled water and dilute HCl. The release of ibuprofen was more sustained in bead than simple mixture and coprecipitate of ibuprofen and sodium alginate. The dissolution rate of ibuprofen was decreased in using of bead that hardened with formaldehyde. The dissolution rate of the drug from the bead was the fastest in 12 hour dried beads, 1.5%-sodium alginate concentration and 1%-calcium chloride concentration. Sodium alginate bead can be used as a sustaind release drug delivery system of water-insoluble drugs.

• Polymer(Korea)
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• v.37 no.3
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• pp.294-301
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• 2013

Polymersomes made of biodegradable triblock copolymers based on poly(fumaric acid-co-sebacoyl chloride)/PEG (PEG-co-P(FA/SC)-co-PEG) were prepared and studied in aqueous solutions. TEM confirmed the formation of vesicles in aqueous media. Aggregation behavior of the copolymers was studied by fluorescence spectroscopy of 8-anilino-1-naphthalenesulfonic acid, and the critical aggregation concentration (c.a.c.) of the copolymer was found to be ${\sim}26.2{\mu}M$ indicating desirable stability of the vesicles. Dynamic light scattering revealed that the size of the vesicles was distributed within the range of 170-270 nm. Turbidity measurements confirmed the relative short-term stability of the polymersomes. Carboxyfluorescein, a hydrophilic compound, was simply encapsulated in the vesicles during polymersome preparation. The release of encapsulant from the polymersomes at 25 and $37^{\circ}C$ lasted about 3 weeks, and the rate of release followed a first-order kinetics. The release is speculated to be primarily carried out through diffusion. These results confirm that these polymersomes are promising as controlled-release carriers of various drugs.